Nearly 200 million people are expected to tune-in on Saturday to the competition, which pits singers and bands from different countries against each other in a live final with public voting.

But politics and controversy, as well as security concerns, have threatened to overshadow the competition, especially after a flare up of violence between militants in Gaza and the Israeli Army last week.

Four people in Israel and more than 20 people in Gaza were killed in two days of fighting, before mediators managed to restore a ceasefire, even as rehearsals for the competition were getting underway.

News that Madonna had been booked as a guest performer had provoked opponents of Israel's occupation of the Palestinian territories to demand she re-think her commitment.

But in a statement to CNN, the singer said, "I'll never stop playing music to suit someone's political agenda nor will I stop speaking out against violations of human rights wherever in the world they may be."

"My heart breaks every time I hear about the innocent lives that are lost in this region and the violence that is so often perpetuated to suit the political goals of people who benefit from this ancient conflict. I hope and pray that we will soon break free from this terrible cycle of destruction and create a new path towards peace," the statement continued.

There remains some confusion over whether Madonna will actually take the stage.

The European Broadcast Union (EBU), which has overall responsibility for the annual event, said it has not yet completed the paperwork necessary for Madonna to perform.

"The EBU can confirm that no final decisions have been made, or agreements signed, regarding a performance by Madonna at the Eurovision Song Contest 2019," a Eurovision spokesperson told CNN.

But Josh Hantman, a spokesperson for Sylvan Adams, the Israeli-Canadian entrepreneur who is footing the bill for Madonna's performance, said the financial part of the contract had been settled.

Hantman also said that Madonna was already "on her way" to Israel to take part in Saturday's show.

CNN